Method and apparatus for low-latency camera control in a wireless broadcasting system

ABSTRACT

Systems, methods, apparatus, methods and computer program code are disclosed for operating automated video broadcasting systems and include capturing, by a video camera, video data at an event site. Scene description data is extracted from the video data, and the scene description data is transmitted, over a wireless communication network, to a video processing system. The video data is transmitted separately from the scene description data from the video camera to the video processing system over the wireless communication network.

FIELD

The present invention relates to methods and apparatus for operating awireless camera system. More particularly, some embodiments relate tomethods and apparatus for wireless protocol optimization in a wirelessvideo broadcasting system.

BACKGROUND

Multiple video cameras are often used in conjunction with the productionof television and other broadcast programs. In many situations, such asthe production of sporting, news or other broadcast programs, it is noteconomically viable to send large camera crews to cover events. Onepossible solution is to set up automated camera systems at the event'ssite to minimize labor and deployment costs. Automated camera systemstypically capture video data, and process these data in real-time foruse in identifying and tracking objects and actions on the field (e.g.,such as tracking a player on the football field, etc.). Scenedescription data (“SDD”) are characteristic data used in such systems toallow the identification and tracking of such objects and actions. Somevideo cameras extract this SDD from the video being captured, andtransmit the SDD along with the video stream to a central videoprocessing unit (e.g., located at a local or remote broadcast productionfacility). The video processing unit analyzes the SDD from one or morevideo cameras, and transmits camera control data (“CCD”) back to eachvideo camera to control the operation and orientation of each camera.

The use of such automated camera systems can provide a number of costsavings and efficiencies in broadcast program production. Unfortunately,however, many events that are broadcast are in locations (such asarenas, fields, etc.) that do not allow for cost-effective wiredconnections between one or more automated video cameras and a centralvideo processing unit. For example, if a high school soccer match is tobe broadcast, it is simply not cost effective to connect the camerasystems to a video processing unit using cables (such as Ethernetcables). Such cabling often requires that conduit be run between thedevices, and frequently, to be effective, the cabling and conduit needsto be buried so it is not damaged or does not interfere with theactivities in the field. Therefore, it is desirable to connect one ormore video cameras with one or more video processing units via awireless connection. Because automated cameras require the ability tosend both video data and SDD (and to concurrently receive the CCD), eachof these data streams may compete with each other for wireless resources(such as radio channel(s), timeslots, etc.). Further complicating theallocation of wireless resources is the fact that video data,particularly high definition video data, requires substantial capacityfor transmission.

It would be desirable to provide methods and apparatus to manage andoptimize the use of such wireless resources, allowing the best possiblevideo broadcast performance in situations where one or more videocameras are in wireless communication with one or more video processingunits.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of portions of a broadcast event productionconfiguration.

FIG. 2 is a block diagram of portions of a system in accordance withsome embodiments of the present invention.

FIG. 3 is a further block diagram of portions of a system in accordancewith some embodiments of the present invention.

FIG. 4 is a flow diagram of a process in accordance with someembodiments of the present invention.

DETAILED DESCRIPTION

Systems, methods, apparatus, means, and computer program code aredisclosed for operating automated video broadcasting systems and includecapturing, by a video camera, video data at an event site. Scenedescription data is extracted from the video data, and the scenedescription data is transmitted, over a wireless communication network,to a video processing system. The scene description data is transmittedin a plurality of data packets prioritized to have a reducedtransmission delay over the wireless communication network. The videodata is separately transmitted from the video camera to the videoprocessing system over the wireless communication network.

Pursuant to some embodiments, broadcast systems operated pursuant to thepresent invention achieve lower latency and higher transmissionreliability when using wireless communication networks by use ofwireless protocol optimization. Pursuant to some embodiments, thewireless protocol optimization is configured to allocate availablewireless communication resources to different data streams (includingdata streams carrying scene description data, video data, and cameracontrol data). The optimization, in some embodiments, is based on theinformation contained in the scene description data and the cameracontrol data.

With these and other advantages and features that will become apparent,embodiments may be more clearly understood by reference to the followingdetailed description, the appended claims, and the drawings attachedhereto.

Applicants have recognized that there is a need for methods, systems,apparatus, means and computer program products to optimize videobroadcast performance in environments using one or more wireless videocameras.

Pursuant to some embodiments, the present invention provides apparatusand methods that achieve lower latency and higher transmissionreliability in a wireless video broadcasting system by means of wirelessprotocol optimization. Pursuant to some embodiments, the wirelessprotocol optimization is configured to allocate available radioresources to different data streams (including data streams carryingSDD, CCD, and video data). The optimization is based on the informationcontained in the SDD and CCD. Applicants have discovered that apparatusand methods pursuant to the present invention provide desirableimprovements in latency and reliability as compared to implementationswhere all the data streams from each of the video cameras at a broadcastevent are transmitted with equal priorities, and where the wirelesscommunication protocols are configured solely based on current radiochannel conditions and data traffic loads irrespective of theinformation contained in the SDD and CCD. The result is improvedperformance, operation and control of wireless video cameras in theproduction of broadcast events.

A number of concepts and terms are used herein to describe features ofsome embodiments. For example, those skilled in the art, upon readingthis disclosure, will appreciate that some video streams and signalstransmitted wirelessly pursuant to the present invention may be“compressed” or generated using a variety of different “compression”techniques, where “compression”, as used herein, refers to thetransformation of a signal into another form for transmission thatconsumes less capacity than transmitting the un-transformed signal wouldconsume. For example, the term “compression”, as used herein, includes“converting”, “encoding” and other transformations of a signal toanother signal that consumes less capacity than the original signal whenstored or transmitted.

In general, as used herein, the term “wireless network” refers towireless communication networks including those defined by IEEE Standard802.11, as well as licensed radio systems such as IEEE Standard 802.16,or the like.

In general, as used herein, the term “uplink” (when referring tocommunication between a video camera and a video processing center orvideo processing computer system), refers to transmissions thatoriginate from the video camera and end at the video processing center,and the term “downlink” refers to transmissions that originate at theprocessing center and end at a video camera.

Features of some embodiments will now be described by reference to FIG.1 which is a simplified block diagram of portions of a system 100pursuant to some embodiments. In the simplified block diagram of thesystem 100, only selected components are depicted in order to illustratethe general configuration of some embodiments. Further details of theselected components and the operation of the system will be providedfurther below in conjunction with FIGS. 2-4.

As shown in FIG. 1, embodiments of the present invention utilize asystem 100 in which one or more video cameras 102 are in wirelesscommunication with one or more video processing centers 120. The videocameras 102 are deployed at an event location 130 and are positioned toallow the capture of video of an event for use in the creation of a cutprogram for transmission to a production facility. Those skilled in theart will appreciate that the program or data created by the videoprocessing center 120 may be further manipulated, edited, cut orredistributed by a local or remote production facility (not shown).Embodiments described herein are focused on the communication andinteraction between the video cameras 102 and one or more broadcastingcomputers or centers 120, and the operation or configuration of anyproduction or distribution facilities is not described. Pursuant to someembodiments, some or all of the video cameras 102 are in communicationwith one or more centers 120 via wireless communication links.

As depicted, one or more video cameras 102 are positioned to cover thescene 130 at the event. While two video cameras 102 are shown in FIG. 1,those skilled in the art will appreciate that any number of videocameras 102 may be in communication with one or more video processingcenters 120. Any or all of these video cameras 102 may be a combinationof steerable and static smart cameras such as video cameras withadvanced video analysis capabilities. Pursuant to some embodiments, oneor more of the video cameras 102 are capable of processing uncompressedvideo streams locally at the video camera, and further are capable ofextracting SDD. SDD may include any information about the scene 130 thatcan be extracted based on vision analysis or other sensors capable ofmeasuring data from the scene 130. For example, SDD may includeestimates of the video camera's 102 parameters (e.g. camera'sorientation and position) or recognition, modeling, and tracking offoreground objects. SDD may also be or include image representations(pixels) of foreground regions, which are referred to as sprites.

Each of the video cameras 102 is in communication with a videobroadcasting center 120 via a wireless communication link. In someembodiments, one or more additional video cameras 102 may be in wiredcommunication with the video broadcasting center 120 as well. The videocameras 102 transmit video stream data and SDD to the video broadcastingcenter 120 over the wireless communication link for use in theproduction or creation of a broadcast program. The video cameras 102also receive CCD from the video broadcasting center 120 over thewireless communication link for use in controlling the operation of thecamera.

For the purpose of describing features of some embodiments, the wirelesscommunication between the video cameras 102 and the video processingcenter 120 will be described as using the IEEE Standard 802.11communications protocol; however, those skilled in the art willappreciate that embodiments may be used with other packet-based wirelessprotocols or communication networks with equally desirable results. Ingeneral, the uplink and downlink transmissions to and from the videocameras 102 and video processing center 120 compete for wirelessresources (e.g. radio channel(s), timeslots, etc.) when unlicensed radiosystems such as IEEE 802.11 are used. Even data streams sent to and fromthe same video camera 102 (e.g. video stream and SDD) may compete witheach other for these resources. Embodiments utilize radio resourcemanagement (“RRM”) techniques to resolve this competition for resources.For example, data streams may be allowed to access a radio channel atrandom, but their access rights may also be influenced by variousprioritization/reservation schemes. RRM mechanisms, which are built intowireless protocols, are technology-specific, but their underlyingprinciples are similar.

Pursuant to some embodiments, the resource management of the wirelesscommunications is performed using one or more wireless interfaceoptimizers (“WIOs”—not shown in FIG. 1). As will be described below,these WIOs may be deployed in a number of different ways, includingembodiments where the WIO units are deployed with each video camera 102(described in conjunction with FIG. 2) and embodiments where the WIOunits are deployed in a central location (described in conjunction withFIG. 3). According to some embodiments, each WIO unit optimizes thewireless protocol parameters associated with a wireless communicationconnection or link. The optimization is done based on the severalinputs, including the SDD, the CCD, and one or more wireless systemparameters (referred to herein as “WSPs-In”) that describe the state ofthe wireless link, such as the signal-to-noise-and-interference ratio(“SNIR”) and packet loss rate (“PLR”). The outputs of a WIO unit arewireless system parameters (“WSPs-Out”) that control the behavior of thewireless protocols, such as the congestion window (“CW”) and modulationand coding scheme (“MCS”). Note that the type and the number of WSPs, aswell as the logic inside the WIO depends on the particular wirelesstechnology used (e.g. Wi-Fi, WiMAX, or WiGig). One WIO unit optimizesone wireless interface. Thus, coordination between multiple WIO unitsmay be needed to optimize a wireless network.

As discussed above, in some embodiments, some or all of the videocameras 102 are capable of extracting SDD information from videocaptured by the camera. The specifics of a method for extracting SDDfrom an uncompressed video sequence are outside the scope of the instantinvention, and are not described in detail herein. Once the SDDinformation is captured and identified by a camera 102, the SDD aretransmitted wirelessly from the video camera 102 to the video processingcenter 120.

Pursuant to some embodiments, the SDD extraction is performed by an SDDextractor (items 212 and 312 of FIGS. 2 and 3, respectively). In someembodiments, the SDD extractor is configured as a part of the camera102, while in other embodiments, the SDD extractor may be external tothe camera 102 (e.g., as a module in communication with a camera 102which is otherwise unable to extract SDD).

As will be explained in detail below, in the case of the centralizedembodiment (FIG. 3), WSPs-In data describing the state of the wirelesslink (such as SNIR and PLR) are also transmitted wirelessly from thevideo camera 102 to the video processing center 120. Video data is alsowirelessly transmitted from the video camera 102 to the video processingcenter 120. As used herein, the transmission of the SDD and the videodata are said to be transmitted “separately” to the extent that the SDDand the video data (and/or other data such as CCD) are transmitted indifferent streams of packets that may be associated with differenttreatments (such as different priorities). For example, although bothSDD and video data may be transmitted over the same wireless connectionbetween video camera 102 and video processing center 120, the SDDpackets may be transmitted using a different priority or treatment(e.g., by setting a marker in the packet headers associated with the SDDpackets) than the video data packets.

Pursuant to some embodiments, a number of benefits are obtained byextracting SDD at the video camera 102 (or at a device such as aseparate SDD extractor associated a video camera 102) rather thanextracting SDD at a remote device or system, such as the videoprocessing center 120. For example, pursuant to some embodiments, SDDpackets may be prioritized and transmitted over a wireless communicationnetwork with reduced latency as compared to the video data packets(e.g., which are transmitted “separately”). This allows transmission ofSDD with reduced latency compared to the transmission of the videopackets and allows faster, and more accurate camera control. Further,more accurate and reliable camera control can be obtained, as the SDD isextracted from a lossless video at the video camera 102 instead ofextracting the SDD from a lossy (compressed and distorted by packetlosses) video at the video processing center 120.

The multiple SDDs associated with each of the different video cameras102 are analyzed in the processing center 120 and, based on thisanalysis, video camera 102 control decisions are made, which may includeoperations such as steering a video camera 102 and initiating handoverbetween different video cameras 102 via the processing center 120. Thecontrol decisions are wirelessly conveyed to the video cameras 102 inthe form of CCD messages, which may specify the camera priority,orientation, zoom, and other camera-specific settings. The CCDs,together with SDDs and WSPs-In, are passed to the WIOs, where wirelessprotocol parameters of the different wireless interfaces (where eachvideo camera and the video processing center 220 has its own associatedwireless interface optimizer) are jointly optimized. Finally, the CCDthat control the video cameras 102 are transmitted back to the videocameras 102 over the wireless communication link. In the case of thecentralized embodiment (FIG. 3), the WSPs-Out that control the wirelessprotocol parameters associated with each camera are also transmittedback to the video cameras 102 over the wireless communication link.

As shown, the system 100 includes a video processing center 120.Although a single center is depicted, in some embodiments, multiplecenters or processing stations may be used. The video processing center120 may be a typical production control station, with video editing,camera controls, and switcher functionalities. Pursuant to someembodiments, the video processing center 120 also has one or morewireless interfaces allowing communication between the center 120 andthe video cameras 102. Further, in some embodiments, including thecentralized processing embodiment described further below in conjunctionwith FIG. 3, the video processing center 120 may also have one or morecamera wireless interface optimizers (“WIOs”, not shown in FIG. 1)allowing the center 120 to optimize wireless protocol parameterspursuant to the present invention. The video processing center 120receives video data from each of the video cameras, operates on thevideo data, and generates a cut program that may be transmitted to abroadcast facility for final production and distribution. The videoprocessing center 120 also issues camera control commands for use incontrolling the video cameras 102. These camera control commands aretransmitted to some or all of the video cameras 102 via wirelesscommunication links.

Further details of some embodiments of the present invention will now bedescribed by reference to FIG. 2 which is a block diagram depictingcertain components of a system 200 pursuant to the present invention. Inparticular, FIG. 2 depicts components of a video camera 202 incommunication with a video processing center 220 (where items 202 and220 may be in wireless communication at an event's site as depicted inFIG. 1). The system 200 of FIG. 2 depicts an embodiment where the videocamera 202 has a wireless interface optimizer (WIO) 208 as part of (ordistributed with) the video camera 202. Only a single video camera 202is shown in FIG. 2 for ease of illustration. In a typical broadcastevent production environment, multiple video cameras 202 may bedeployed, each in communication with the video processing center 220over wireless networks. Video camera 202 includes a number ofcomponents, including the WIO 208, a wireless interface 206, a videocapture and processing module 204, and an encoding and compressionmodule 210.

The system 200, as depicted, also illustrates certain components of thevideo processing center 220. For example, as shown, the system 200includes a wireless interface 222 for communicating with the one or morevideo cameras 202 over a wireless communication network. The system 200also includes components including a camera control module 224, a localwireless interface optimizer 226, a video processor 228 and a switcher230. Some of the components (including the video processor 228 andswitcher 230) may be standard components typically used in theproduction of broadcast events, and are operated as normal to generate acut program for transmission to a production studio for broadcast anddistribution.

In some embodiments, the video camera 202 may be a high definition videocamera, capable of capturing video data and generating high definitionvideo data streams using video capture and processing module 204.Because uncompressed high definition video data streams requireextremely high data rates, which cannot be supported with currentwireless technologies, these video streams currently need to becompressed/encoded before being transmitted to the video processingcenter 220. As a result, a compression/encoding module 210 is provided.Video encoding involves high computational complexity and introducesdelay, which adds to the radio propagation delay during the transmissionof the data from the video camera 202 to the video processing center220. In existing systems, the encoded video stream is decoded at thevideo processing center and the video processing center operates on thedata to extract the relevant SDD. Applicants have discovered, however,that such processing introduces an undesirable delay when camera controlcommands and data are to be generated and transmitted back to the videocamera. For example, as a result of the delay introduced by videoencoding (at the camera), video decoding (at the processing center) andextraction of SDD information (at the processing center), and thetransmission of CCD to the video camera, camera control commands may bedelayed to the point where tracking of the objects or action in thefield, and controlling hand-over between video cameras cannot beperformed in a timely manner. As a result, performance and qualitysuffer in an undesirable manner. Embodiments provide techniques foreliminating or substantially reducing this delay, thereby providingimproved performance and quality.

Pursuant to some embodiments, the compression/encoding module 210performs compression on the video data captured by the video camera 202.The video capture and processing module 204 operates to extract the SDDinformation from a raw uncompressed video stream at the video camera202, and wirelessly transmits the SDD information to the processingcenter. As shown in FIG. 2, the SDD information is fed to a WIO 208 unitand also is transmitted to the video processing center 220 separatelyfrom the encoded/compressed video data. Further, the SDD information istransmitted over the wireless network in a dynamically prioritizedmanner as will be described below. The prioritization, in someembodiments, is performed under control of a WIO 208 associated witheach video camera 202. In the embodiment of FIG. 2, the WIO associatedwith video camera 202 is located at the video camera 202 (in other,centralized systems, the WIO associated with each video camera may belocated at a central location, such as at video processing center220—such embodiments will be described below in conjunction with FIG.3).

As shown in FIG. 2, each video camera 202 transmits two streams of dataover the wireless network to the video broadcasting center 220—an SDDstream (which, as described above, is extracted from the raw video byvideo capture and processing module 204) and which is transmitted withminimal delay, and an encoded/compressed video stream (encoded andcompressed by compression/encoding module 210) and which is transmittedafter some encoding delay.

Pursuant to some embodiments, a video camera 202 may transmit the SDDstream only if its associated video feed has been selected by theswitcher 230 to be cut into the program. At other times (when thespecific video camera 202 has not had its associated video feed selectedfor use), the video camera 202 may send a reduced-size SDD stream.Similarly, pursuant to some embodiments, a video camera 202 that has nothad its associated video feed selected for use may send a reduced-sizevideo stream (e.g., in a lower fidelity), or no video stream at all.

Pursuant to some embodiments, to ensure improved performance anddelivery of SDD without delay, the SDD stream is separated from thevideo stream data and is prioritized for delivery over the wirelessnetwork. Such prioritization may be performed in a number of differentways pursuant to the invention. Several illustrative, but not limiting,embodiments will be described hereafter.

In one embodiment, the video stream and the SDD stream may be separatedusing the IEEE 802.11 quality of service differentiation known as EDCAin the 802.11 standard. In this embodiment, the SDD stream istransmitted from the video camera 202 to the video broadcasting center220 by either (i) polled contention-free hybrid coordination function(“HCF”) controlled channel access (“HCCA”), or (ii) higher prioritymedium access using access categories that lead to lower delays, smalleraverage number of potential retransmissions, and hence higherreliability. The 802.11 standard uses a medium access control protocolin which a contention window is used to randomize the time at which atransmitter (such as the wireless interface 206 of the video camera 202)initiates a frame exchange. The earlier the transmitter attempts theframe exchange, the higher the priority. Using prioritization mechanismsdefined in the 802.11 standard, the contention window start time andsize can be modified such that different transmitters enjoy differentthroughputs, and thereby different priorities. The prioritization can berealized between stations (e.g., to prioritize different wirelessinterfaces 206 of different video cameras 202 at an event), or within asingle station (e.g., to prioritize the transmission of SDD streams overvideo streams from a particular video camera 202). Pursuant to someembodiments, the prioritization of transmission of SDD streams over thetransmission of video streams, as well as the prioritization oftransmission of other streams in systems of the present invention may becontrolled using these techniques.

Other techniques may also be used pursuant to some embodiments. Forexample, cognitive radio mechanisms may be applied to the two separatecamera streams (including the SDD stream and the video data stream), bytransmitting the data in different spectra. For example, in oneembodiment, the TV white space spectrum may be used to transmit thelarge amount of data comprising the encoded video stream, and the 60 GHzlow latency spectrum for the SDD stream. Other spectra may also be usedto control and prioritize the delivery of the different data streamsbetween and among the video cameras 202 and video broadcasting center220 of the present invention.

In still another illustrative embodiment, the two separate data streams(video data and SDD), or part of each, could be sent at differentlicensed frequencies such as channels in the BAS 2.5 GHz range. Forexample, one or multiple channels in the licensed BAS 2.5 GHz rangemight not be used by the intended broadcast service at a given locationand hence may be available for sending the SDD at highest reliability,and some of the video streams would be sent in other spectrum that areless reliable.

As shown in FIG. 2 (as well as in FIG. 3, below), each video camera 202also receives CCD from the video broadcasting center 220. The CCD isused to control each video camera 202, including the camera orientation,camera priority, zoom, and other camera specific settings. CCD may alsobe sent via the wireless network in the downlink to control, forexample, the camera's view and the encoder's parameters. The videocamera 202 receives CCD streams and implements the commands accordingly.Both uplink and downlink communications of SDD and CCD streams,respectively, need to be transmitted at high priority to ensuredesirable operations and performance. As a result, pursuant to someembodiments, to guarantee a high priority transmission, embodimentsutilize CCD to adapt WIO operation (similar to the use of the SDDdescribed above in the uplink communication). Priority mechanismssimilar to what was discussed for SDD uplink prioritization above can beapplied. In general, applicants have found that in some situations,individual camera CCD streams should be prioritized over other cameraCCD streams (based on relative camera priorities) and over the uplink'sstreams. Embodiments of the present invention allow such dynamicprioritization between streams, between data sets, and between cameras.

Further, in some embodiments, in addition to dynamically prioritizingSDD and CCD streams, features of the present invention can be used toprioritize individual video streams from one video camera over othervideo cameras when needed. Or to prioritize different layers of the samevideo stream utilizing layered and scalable video coding methods (e.g.where encoded data is structured into layers, different priority may begiven to different layers of the same video stream). This can beparticularly helpful when unlicensed radio systems are used and radiospectrum is shared in uplink and where transmitters transmit at the samechannel. Further, such dynamic prioritization may also be applied for asystem where the video cameras 202 and the production switcher 230 areoperated by cameramen and a director, respectively. In this case, basedon the switcher 230 state, the video streams may be prioritized toalleviate traffic load on the wireless network.

Reference is now made to FIG. 3 which is a block diagram depictingcertain components of a system 300 pursuant to the present invention. Inparticular, FIG. 3 depicts components of a video camera 302 which aresubstantially similar to the video camera 202 of FIG. 2, except that thevideo camera 302 does not include a wireless interface optimizer(“WIO”). Instead, the functions performed by the wireless interfaceoptimizer to optimize the transmission of signals between video camera302 and video broadcasting center 320 are performed by a WIO 328 locatedat the video broadcasting center 320. That is, the system 300 of FIG. 3uses a centralized architecture for the wireless interface optimizationof components within the system.

As with the system of FIG. 2, the system of FIG. 3 includes one or morevideo cameras 302 positioned to cover a scene at an event. These videocameras 302 may be a combination of steerable and static smart cameras.Uncompressed video streams are processed locally at each video camera306 and SDD are extracted. The SDD is transmitted wirelessly from thecamera system to the video processing center 320, along with the videostream and WSPs-In that describes the state of the wirelesscommunication link, such as SNIR and PLR. The multiple SDDs respectiveto the different video cameras 302 are analyzed in the video processingcenter 320 and, based on this analysis, camera control decisions aremade, which may include operations such as steering the video cameras302 and initiating handover via a switcher 330 at the video processingcenter 320. The control decisions are conveyed to the video cameras 302in the form of CCD messages, which may specify the camera priority,orientation, zoom, and other camera-specific settings. The CCD, togetherwith SDDs and WSPs-In, are passed to the WIOs, where wireless protocolparameters of the different wireless interfaces (camera n wirelessinterface units and the processing center wireless interface unit) arejointly optimized. Finally, the CCD and the WSPs-Out that control thevideo cameras 302 and the behavior of the wireless protocols,respectively, are transmitted back to the video cameras 302.

Applicants have discovered that optimization of the wireless network andtransmissions is simplified in the case of the centralized solution ofFIG. 3 as compared to the distributed system of FIG. 2; however, thesystem of FIG. 3 may present signaling overhead as the WSP informationneeds to be sent and received to and from the video cameras 302. Placingwireless interface optimization units at the video cameras makes theoverall wireless network optimization more difficult, but reduces oreliminates this signaling overhead.

Reference is now made to FIG. 4 which illustrates a method that might beperformed, for example, by some or all of the elements described herein(such as the elements described in conjunction with FIGS. 1-3). The flowchart described herein does not imply a fixed order to the steps, andembodiments of the present invention may be practiced in any order thatis practicable. Note that any of the methods described herein may beperformed by hardware, software, or any combination of these approaches.For example, a computer-readable storage medium may store thereoninstructions that when executed by a machine result in performanceaccording to any of the embodiments described herein.

At 402, video data (and in some embodiments, audio data) from an event(such as a live event to be broadcast) is captured. The video data maybe captured from devices such as the video camera 102 positioned andoperated at the event (such as in the system described in FIGS. 1-3above). As used herein, the phrase “video data” may refer to any signalconveying information about a moving image, such as a HighDefinition-Serial Data Interface (“HD-SDI”) signal transmitted inaccordance with the Society of Motion Picture and Television Engineers292M standard. Although HD signals may be described in some examplespresented herein, note that embodiments may be associated with any othertype of video feed, including a standard broadcast feed and/or a 3Dimage feed. Those skilled in the art will appreciate that during each ofthe processes of FIG. 4, CCD streams may be sent or received by thevideo camera 102 to change its orientation or operation or to inform thevideo broadcasting center 120 of changes in operation.

Processing at 404 includes extracting the SDD information from the videodata captured at 402. In some embodiments, the SDD information isextracted during the video capture process by use of a video capture andprocessing module associated with the video camera 102. The extractionof the SDD information may be performed in a number of ways, usingtechniques known to those skilled in the art.

Processing at 406 includes prioritizing and transmitting the SDDinformation to the video processing system 120. In some embodiments,processing at 408 includes prioritization of the video with respect tothe videos transmitted by other cameras. For example, based oninformation within the extracted SDD or received CCD, a certain camerafeed may be covering (or may be steered to follow) an activity ofinterest, hence this camera's video may be set at a high priority whilethe other cameras' video may be set into low priority to alleviate thetraffic load on the network.

Pursuant to some embodiments, the video stream transmitted from a videocamera 102 may be encoded at an adaptive bit rate that is a function ofthe current wireless network capacity (based on information conveyed byWSPs from the wireless interface optimizer 208 to the wireless interface206). In such a case, this bit rate would be higher when the video iscurrently cut into the program (based on information conveyed in the CCDstream). In some embodiments, processing at 408 includes prioritizationof the video's different layers. For example, when using layered andscalable coding methods, where encoded data is structured into layers,different priority may be given to different layers of the same videostream. Typically, first layer will encode low resolution representationof the video while successive layers will each add more details to thevideo stream. Hence, depending on information received in the SDD andCCD streams and the current network condition, different priorities maybe assigned dynamically to different video layers.

The following illustrates various additional embodiments of theinvention. These do not constitute a definition of all possibleembodiments, and those skilled in the art will understand that thepresent invention is applicable to many other embodiments. Further,although the following embodiments are briefly described for clarity,those skilled in the art will understand how to make any changes, ifnecessary, to the above-described apparatus and methods to accommodatethese and other embodiments and applications.

In some embodiments, multiple wireless interfaces may be supported. Forexample, multiple wireless interfaces could be provided at each cameraand at the video processing center, using different wirelesstechnologies. As a specific illustrative, but not limiting, example, oneinterface could support IEEE 802.11, while a second interface couldsupport communication via IEEE 802.16. As a further illustrative, butnot limiting, example, the multiple wireless interfaces may each supporta different frequency band (e.g., one could be at 2.4 GHz, and anotherat 60 GHz). In some embodiments, part of the system optimization couldbe to select the most appropriate interface based on SDD, CCD and WSPs.Further, one interface could be used for high-priority data (SDD andCCD) and another wireless interface could be used for the video data.

Moreover, although specific hardware and data configurations have beendescribed herein, note that any number of other configurations may beprovided in accordance with embodiments of the present invention (e.g.,some of the information associated with the databases and enginesdescribed herein may be split, combined, and/or handled by externalsystems). Further note that embodiments may be associated with anynumber of different types of broadcast programs or events (e.g., sports,news, and weather programs).

Those skilled in the art, upon reading this disclosure, will appreciatethat FIGS. 1-3 are conceptual block diagrams intended to illustratecertain features of embodiments (such as the communication betweendifferent components), and that certain functions and componentsdescribed in FIGS. 1-3 may be implemented using a variety of devices orcombinations of devices. For example, some of the functions shown asseparate blocks may be implemented using a single component or set ofcomponents.

The present invention has been described in terms of several embodimentssolely for the purpose of illustration. Persons skilled in the art willrecognize from this description that the invention is not limited to theembodiments described, but may be practiced with modifications andalterations limited only by the spirit and scope of the appended claims.

What is claimed is:
 1. A method comprising: capturing, by a videocamera, video data at an event site; extracting scene description data(“SDD”) from the video data prior to transmission to a video processingsystem; transmitting, over a wireless communication network, the SDD tothe video processing system, the SDD transmitted in a plurality of SDDpackets; and transmitting, over the wireless communication network, thevideo data to the video processing system, the video data transmitted ina plurality of video data packets, wherein the plurality of SDD packetsand the plurality of video data packets are prioritized to have adifferent transmission priority based on information in at least one ofthe SDD packets, the information comprising at least one of: recognitionof objects at the event site, tracking of objects at the event site,modeling of objects at the event site, image representations of regionsof the event site, position of the video camera, orientation of thevideo camera, and video camera parameters.
 2. The method of claim 1,further comprising: receiving, by the video camera, camera control data(“CCD”) over the wireless communications network, the CCD transmitted ina plurality of CCD packets prioritized to have a different transmissionpriority based on the information in at least one of the SDD packets. 3.The method of claim 1, further comprising: controlling the wirelesscommunication network to establish a priority of the transmission of theplurality of SDD and video data packets.
 4. The method of claim 3,wherein the controlling the wireless communication network is performedunder control of a wireless interface optimizer.
 5. The method of claim4, wherein the wireless interface optimizer is located at the videocamera.
 6. The method of claim 4, wherein the wireless interfaceoptimizer is located at the video processing system.
 7. The method ofclaim 3, wherein controlling the wireless communication network furthercomprises: controlling the wireless communication network to establish apriority of the transmission of the video data.
 8. The method of claim7, wherein the priority of the transmission of the video data iscontrolled based at least in part on at least one of the SDD and CCDassociated with the video camera.
 9. The method of claim 1, furthercomprising at least a second video camera to capture second video dataat the event site, the method further comprising: controlling thewireless communication network to establish a relative priority of datapackets containing the video data and the second video data.
 10. Themethod of claim 9, further comprising: extracting a second set of SDDfrom the second video data; transmitting, over the wirelesscommunication network, the second set of SDD to the video processingsystem, the second set of SDD transmitted in a second plurality of SDDpackets; and transmitting, over the wireless communication network, thesecond video data to the video processing system, the second video datatransmitted separately from the second plurality of SDD packets.
 11. Themethod of claim 10, wherein the second video data and the secondplurality of SDD packets are transmitted with different priorities,where the priorities are established based on the information in the SDDand the second set of SDD.
 12. The method of claim 10, furthercomprising: receiving, by the second video camera, second CCD over thewireless communications network, the second CCD transmitted in aplurality of CCD packets having a different transmission priority thanat least one of the SDD and the video data packets.
 13. The method ofclaim 12, wherein a relative priority of transmission is establishedbased on at least one of (i) the information in the SDD and the secondset of SDD, and (ii) information in the CCD and the second CCD.
 14. Themethod of claim 1, further comprising: compressing the video data priorto transmitting the video data to the video processing system.
 15. Avideo camera, for capturing event video data at an event site,comprising: a video capture and processing subsystem for processing thecaptured event video data and extracting scene description data (“SDD”)from the event video data; a compression subsystem for compressing theevent video data; and a wireless interface receiving at least a firstwireless system parameter to control a transmission priority of thewireless interface, the wireless interface operable to wirelesslytransmit the compressed event video data in a first transmissionpriority, and to wirelessly transmit the SDD in a second transmissionpriority, wherein the first transmission priority and the secondtransmission priority are based on information in the SDD, theinformation comprising at least one of: recognition of objects at theevent site, tracking of objects at the event site, modeling of objectsat the event site, image representations of regions of the event site,position of the video camera, orientation of the video camera, and videocamera parameters.
 16. The video camera of claim 15, wherein thewireless interface further receives CCD from a video processing system,the CCD transmitted in a plurality of data packets prioritized in athird transmission priority.
 17. The video camera of claim 16, furthercomprising: a wireless interface optimizer, the wireless interfaceoptimizer generating the at least first wireless system parameter basedon at least one of the SDD and the CCD.
 18. The video camera of claim15, wherein the at least first wireless system parameter is receivedover the wireless interface from a video processing system.
 19. Anon-transitory, computer-readable medium storing program code executableby a computer to perform a method, said method comprising: capturingvideo data at an event site by a video camera; extracting scenedescription data (“SDD”) from the video data prior to transmission to avideo processing system; transmitting, over a wireless communicationnetwork, the SDD to the video processing system, the SDD transmitted ina plurality of SDD packets; and transmitting, over the wirelesscommunication network, the video data to the video processing system,the video data transmitted in a plurality of video data packetsseparately from the SDD packets, wherein the plurality of SDD packetsand the plurality of video data packets are prioritized to have adifferent transmission priority based on information in at least one ofthe SDD packets, the information comprising at least one of: recognitionof objects at the event site, tracking of objects at the event site,modeling of objects at the event site, image representations of regionsof the event site, position of the video camera, orientation of thevideo camera, and video camera parameters.
 20. The non-transitory,computer-readable medium storing program code executable by a computerto perform a method of claim 19, said method further comprising:receiving camera control data (“CCD”) over the wireless communicationsnetwork, the CCD transmitted in a plurality of data packets prioritizedseparately from said plurality of video data packets and said SDDpackets.